Fluid pressure operated circuit interrupter



Nov. 16, 1948. 5, 55 2,454,189

FLUID PRESSURE OfERATED CIRCUIT INTERRUPTER Filed Jan. 12. 1946WITNESSES: INVENTOR Gerhard [604765. BY W 4 AIZTORINEY Patented Nov.16,1948

FLUID PRESSURE OPERATED CIRCUIT INTERRUPTER Gerhard Lenties, Pittsburgh,Pa assignor to Westinghouse Electric Corporation, East Pittsburgh, Pm, acorporation of Pennsylvania Application January 12, 1946, Serial No.640,838

7 Claims. (Cl. 200-82) may be equipped with a heavy spring for effectingrapid opening of the contact elements, and a piston subject tocompressed air for closing the contact elements, the completed assemblybeing preferably capable of eilecting an open-closeopen operation withina time interval of less than 1'7 cycles for certain classes of 60 cycleservice. Because of the power and speed of operation thus required for acircuit breaker of this class, it is desirable to provide an operatingmechanism having maximum simplicity and ruggedness of de-' sign, butnevertheless adapted for smooth and relatively shock-free operation.

In the construction of a circuit breaker oi the above type, in order toprevent development of excessive shock and vibration during operation ofthe powerful actuating piston, it has been proposed to control thesupply of compressed air in such a manner as to insure relatively smoothand safe acceleration of the piston, particularly during initialmovement. For this purpose there has been provided a control valve meansfunctioning to restrict or reduce the rate of supply of compressed airto the piston cylinder during initial movement of the piston, anddesigned to move quickly from a throttling position to an open positionfor permitting quick final buildup in pressure, following apredetermined initial movement of the piston, preferably at the start ofcompression of the accelerating spring or other load such as at thepoint in its traverse corresponding to the initial touching of thecontact elements of the circuit breaker. In this way, the piston isprevented from acquiring such a velocity as might result in undesiredslamming during operation of the circuit breaker, while full operatingforce becomes available for overcoming any resistance to final closingof the breaker contact elements. In the co-pending application of JamesM. Cumming, filed April 21, 1945, Serial Number 589,581, now PatentNumber 2,434,549,

disclosed a circuit breaker having a control valve means embodying apositive latch for holding the control valve means in its throttlingposition against the force of a spring, together with means forreleasing the latch at the proper time, including a plurality ofinterlocking levers.

It is the object of my invention to provide a new and improved controlor throttle valve mechanism of the above type, in which rugged andsimple features of construction arecombined to promote positiveoperation and to minimize the effect of friction on the speed ofoperation of the mechanism.

Another object of the invention is to provide an improved throttle valvemechanism embodying a minimum number of operating parts, thusfacilitating installation of the mechanism in a circuit breakerequipment of existing design.

Other objects and advantages of the invention will appear in thefollowing more detailed description thereof, taken in connection withthe accompanying drawings in which:

Figure 1 is a diagrammatic view, partly in section, of the operatingportions of a fluid pressure operated circuit breaker equipment havingassociated therewith a preferred form of control valve mechanismconstructed in accordance with the invention; 4

Fig. 2 is a fragmentary sectional view taken partly on the line II II ofFig. 3 of the control valve mechanism shown in a closed positioncorresponding to the open position of the circuit breaker; and

Fig. 3 is a sectional view taken substantially along the line IIIIII ofFig. 2.

Referring to the drawing, in Fig. 1 there is illustrated in diagrammaticform a portion of a single pole unit of a fluid-pressure-operatedcircuit breaker, comprising a suitable frame structure (not shown)supporting stationary contact elements 5 in the power circuit to becontrolled, a movable resilient contact element 8 cooperative therewithand secured to a rod I, a cylinder I0 having mounted therein anoperating piston II, and a piston rod l2, the upper end l3 of which ispivotally connected to the rod 1 through the medium of a beam [4fulcrumed on a stationary pin I5. A coil spring I! is mounted incooperative relationship with the movable contact element 6 for urgingthat element toward an open circuit position. The piston II isresponsive to the pressure of air admitted to a pressure chamber 20 foractuating the piston rod l2, beam i4 and rod 1 to move the contactelement 6 into granted J nu y 1 43, I 1 e mple; there is circuit closingengagement with the stationary contact elements 5, in opposition to theforce exerted by opening spring ii and resilient contact element 3.

For maintaining the circuit breaker elements Just described in circuitclosing position, the circuit breaker apparatus is further provided witha transversely disposed beam 22, one end of which is Journaled on a pin23 carried by a link 24 that is in turn pivotally connected to a pin 25carried The latch mechanism 3i may be of any suitable design and, asillustrated, com-prises a main latch member 32 Journaled on a stationarypin 33 secured to the frame structure, a release pawl 34 pivotallyconnected to the frame structure by means of a pin 35 for cooperationwith the latch member 32, and an auxiliary latch member 36 adapted forcooperation with the pawl 34. The main latch member 32 has a surface 38adapted for latching engagement with the roller 30, and an extension 40adapted for interlocking engagement with a portion of the pawl 34 forresisting clockwise movement of-the main latch member about pin 33 underthe force tending to raise the end of the beam 22 carrying the roller,and thus ending to effect disengagement of the latch member 32 from theroller. For biasing the main latch member 32 in a counter-clockwisedirection, there is provided a spring 42, which is interposed between asuitable lug on the frame structure and the head of a link pivoted tothe latch member.

-For tripping the latch mechanism 39, there is provided a trip coil 44,which is adapted to be energized through the medium of a suitable tripcontrol circuit (not shown) for causing upward movement of an armaturecarrying a plunger that is operatively aligned with a portion of thepawl 34. The pawl 34 is normally urged into the position shown in Fig. lby means of a spring 4i, which is adapted to yield upon operation of thepawl by the trip plunger 45. The auxiliary latbh member 36 isinoperative when the parts are positioned as shown in Fig. l, but servesto hold the pawl 34 out of interfering engagement with latch member 32when the beam 22 and other operating elements of the circuit breaker arein circuit opening position. A coil spring 49 is interposed between aportion of the cylinder structure i I and a lug 53 on the auxiliarylatch 36, and acts to tilt the latter in a clockwise direction about pin35, causing the lug Bill to carry the pawl iii in the same direction;when the end of the beam 22 carrying roller 3a is swung upwardly duringa circuit breaker opening operation. It will be noted that a lug 5icarried on the upper end of auxiliary latch 35 is adapted to be engagedby the free end of the beam 23, when that beam is moved to the circuitclosing position as shown in Fig. 1. With the auxiliary latch member 35thus held down, the spring ii is permitted to maintain the pawl 34 ininterlocking engagement with the main latch member 33.

For controlling the supply of fluid under pressure to the chamber 23,there is provided a magnet valve assembly, generally indicated at 55,comprising a casing having a valve chamber 56 iii communicating with afluid supply pipe 31, which may be connected to any suitable source offluid under pressure. Within chamber 56 is mounted an inlet valve 58 forcontrolling communication from the valve chamber to a passageway 60leading to the pressure chamber 20. The supply valve 58 is normallyurged toward a seated position by a coil spring 82 mounted in the valvechamber 56, and is provided with a valve stem 33 which extends upwardiyand terminates in an armature portion (not shown) movably disposedwithin a magnet coil carried by the frame structure. The magnet coil 85is adapted to be energized through the medium of a suitable controlcircult (not shown) which may be arranged in any a proved and well knownmanner for insuring the desired automatic operation of the circuitbreaker equipment. The valve stem 63 also carries a discharge valveelement 61 which is operative to vent the passagway 60 to atmospherewhen the supply valve element 58 is in its seated position, as shown inFig. 1. Upon energization of the. magnet coil 65, the stem 63 is shifteddownwardly to close the valve element 61 while opening the supply valve58 to effect supply of fluid under pressure to the pressure chamber 20above the piston ii. i

It is not deemed necessary to illustrate the control circuits for themagnet coils 44 and 65, but it will be understood that any suitablecircuit breaker controlling system may be provided to furnish theusualfeatures of automatic operation well known in the circuit breaker art.For example, the trip coil 44 may be arranged for energization inresponse to development of a fault in the main circuit controlled by thecircuit breaker, or alternatively to be subject to manual control. Ifthe circuit breaker equipment includes means for effecting a quickautomatic reclosing operation following an opening operation in responseto a fault, the circuit for energizing the magnet coil 85 may bearranged to initiate energization thereof instantaneously upon trippingof the circuit breaker apparatus or soon thereafter, to thus insure asubsequent reclosing operation with minimum loss of time.

According to the invention, a throttle valve assembly, indicatedgenerally by the reference character I0, is provided for controlling therate of supply of fluid under pressure through the passageway 60 to thepiston chamber 20 at a rate determined in accordance with the operationof the circuit breaker. The throttle valve assembly includes a casingportion ii carried on the cylinder i0, and having a suitable bore 13disposed substantially vertically and in intersecting relation withrespect to a passage'iia communicating through a pipe H with thepassageway 60. As shown diagrammatically in Fig. 3, passageway 16extends through the casing section 6i and wall of cylinder ill to thepiston chamber 20. A restricted bypass i4 is formed in the casingsection ii, as is best shown in Fig. 3, for permitting flow of fluidaround the bore 13 at a rate determined "by adjustment of ascrew-threaded valve elementid. Slidably mounted in the vertical bore i3is a valve element i8, which is urged downwardly under the force or acoil spring 19 that is interposed between the lower end of the valveelement and a cap carried by the casing section ii and secured theretoby suitable means, such as bolts 32. With the valve element 18 held inits lowermost position, as shown in Fig. l, the passageway 13 ismaintained open so that flow of fluid under pressure is virtuallyunrestricted.

n the other hand, when the valve clement id is shifted to its uppermostposition, ee is best shown in Fig. 2, flow oi fluid under pressure isli-mltedto the flow area of the bypass The throttle valve clement i8 isarranged ior operation in accordance with operation of the piston rod 12and associated elements of the circult breaker. For this purpose thevalve element is has secured thereto a stem which extends upwardlythrough the bore l3 and through a suitably packed aperture in the capmember 80, the upper end of the stern carrying a clevis member iii. Theparallel walls oi clevis member 9! are apertured to receive a pin us towhich is pivotally connected-a movable, substantially vertically alignedlatch member so. The latch member all a lug 96 disposed thereon justbelow a sloping cam surface 96, which is adapted to be urged intoengagement with a roller 3? iournaled on a pin {f3 carried by pair ofupwardly extending arm portions lull of the cap members so. Univ one 02the portions Mill is illustrated in the sectional views included in thedrawing. A small pring is interposed between an upper flat surface oithe olevis member 5i and a lower corner suriace of latch member 95 forbiasing the latch member toward the roller Si. also operatively alignedwith the cam surface 56 of the latch member is an extension of the pin28 which, as already explained, operatlvely connects the beam 22 to thepiston rod 52.

For providing a lost motion connection be= tween the clevis member 9iand the beam 22 of the circuit breaker mechanism, there is provided abifurcated link member generally indicated by reference character till,which preferably comprises spaced parallel portions, joined at the upperand lower ends, only one .02. these portions being represented in thedrawing. The lower end of the linlr member lid is pivotaliy connected tothe pin 92, between the spaced portions of clevis member ill. The linkmember has formed therein an elongated slot into which both the end ofpin 253 and the roller 98 are adapted to extend, as indicated in Fig. lof the drawing. Mounted on the uppermost end of the link member lid is aset screw lid which may be adjusted and locked in place by means oi alock nut H6, to provide means for limiting the traverse within the slotH2 or the pin 23 carried by beam 22. When the bear 2:. is tilted to theopen position oi the circuit breaker, as indicated in Fig. 2, the pin 23engages the end of the set screw H5 to lift the link member till, stem90 and valve element iii.

In operation, it the circuit breaker equipment is disposed in itscircuit closing position, as shown in Fig. 1, the beam 22 is held in asubstantially horizontal position with the roller 30 in latchingengagement with the main latch member 32, so that the circuit breaker isheld positively in the circuit closing position against any forcetending to open the contact elements 5 and 5. At the same time thespring 19 is offective to hold the throttle valve element IS in itslower or open position, as shown in Fig. 1, while the latch member 94 isalso disposed in its lowermost or unlatched position, with the lug 96thereof located beneath the roller 9?.

If it is desired to efiect an opening operation or the circuit breaker,the magnet coil 54 is energized through the medium or the usualcontrolling circuit, as already explained, whereupon the plunger 45 isquickly raised to disengage the pawl M from the main latch member as.Due

to the relatively small area oi contact between the inclined suriace oithe main latch moms her and the roller 89, the spring 32 is unable toresist the slight clockwise movement of the latch required to releasethe beam 22 and the latter is consequently moved upwardly about pin 223,while rod ii, beam i i, and rod a are at the some time actuated by thespring ill to effect disengagement of the contact element from thecontact elements The piston ii is carried upwardly during the upwardmovement of the piston rod i2 but it the circuit breaker is equipped fora quick automatic recioslng operation, the operation or the usualauxiliary reciosing means (not shown) re" sults in energlzatlon oi themagnet coil liii in time to operate th supply valve for admittingcompressed air to the piston chamber 2b before piston it has reached itsuppermost position. Upon the resultant supply of compressed air tochamber 2d, the upward motion of the piston M will thus be reversedprior to any engagement between pin and to the set screw i to mounted onthe upper end oi the slotted linlr member no. The throttle valve element"it thus remains in its full open position to insure sub stantiallyunrestricted flow of compressed air through passageway to, pipe ii, andpassageway to pressure chamber 2Q, to furnish the maximum force neededfor reversing the movement of the mechanism and causing quick reclosureof the circuit breaker.

If the fault in the'controlled circuit has not been removed at the timewhen the reclosure of the circuit breaker occurs, the trip coil ill willagalns be energized and coil t5 will be deenergized for venting thepiston chamber 28 to atmosphere, thereby rendering spring ll againoperative to open the circuit breaker. It will be understood thatsuitable dump valve means may be provided for augmenting the dischargeof compressed air from piston chamber 2b in order to promote quickupward movement of piston ll. One form of such dump valve and a suitablecontrol circuit for the complete mechanism is shown in Patent No.2,361,178, issued October 24, 1944 to James M. Cumming, and assigned tothe assignee of the present application. For the purpose of disclosingthe present invention, however, it is deemed unnecessary to show such adump valve and control circuit in the drawing.

Assuming that the circuit breaker is moved to its circuit openingposition with the contact element 6 held out of engagement with contactelements 5 under the force of spring ll, it will be apparent that thebeam 22 will be moved to the position illustrated in Fig. 2 of thedrawing. At this time, the operating piston Ii will be moved to itsuppermost position within cylinder it, while the pin 28 carried by thepiston rod l2 and beam 22 will be carried into engagement with the setscrew M5 for raising the link llii, stem 60 and valve element iii to thethrottlingposition as illustrated in Fig. 2. As the latch. 9c is at thesame time carried upwardly, the lug E35 thereof is caused to rideoverthe roller Q7 and then to engage that element under the force exerted byspring Hi2, so that the valve element '58 will then be latched in itsupper or throttling position to limit the communication between thepassageway Gil and piston chamber 20 to the how area of the bypass it.11

If the controlling circuit for the circuit brea i is now energized inthe usual manner tofcause acccneo a closing operation, the consequentenergizatio'n oi the magnet coil 85 of the magnet valve device 55eifects unseating oi the supply valve element 58 against the iorce ofspring 82, while discharge valve 81 is moved to its seated position.Compressed air is then supplied from the usual source by way oi? pipe51, valve chamber 56, past the unseated valve element 58, thence throughpassageway to, pipe i1 and restricted bypass 14 to the piston chamber20. The piston ii is thereby moved downwardly by the pressure of air foroperating the rod l2, beam i4 and rod '5 tobring the movable contactelement 6 toward the contact elements l5.

It will be understood that although suillcient compressed air is quicklysupplied by way of the communication Just described, including therestricted bypass IQ, to effect prompt closing movement or theassociated circuit breaker operatin elements, the increase of pressureor fluid in chamber it] is nevertheless so controlled as to prevent thepiston i i and other movable elements from acquiring an excessivevelocity during the initial operation. As the piston it continues itsdownward movement, the pin 28 carried by piston rod it engages the camsurface 86 of latch mem= her at and for es the latter to the left, asviewed in Fig. 1, so that the lug 9b is released from the roller ill.The spring lid is thereby rendered efiective to shift the assembledvalve element l9, stem til, latch member so and linlr member libdownwardly. The exact point at which th pin 22 releases thespring-pressed valve element lit may be varied somewhat by properadjustment of the stem ilil with respect to the valve element it. itbeing observed that a, loci: nut 11% is attached to the lower threadedend or the stem for fixing these elements in the desired position.

With the valve element it] thus shifted to its open positionsubstantially instantaneously, the supply of compressed air to thepiston chamber is continued at a suddenly increased rate of flow, andthe air pressure in chamber Ed is thus increased quickly so thatsufficient force is exerted on the piston ii to effect final movementthereof to the fully closed position of the circuit breaker, regardlessof any increase in resistance to such movement that might be causedduring final closing operations oi the contact elements 6: and

From the foregoing it will be seen that an improved control valvemechanism constructed in accordance with my invention may be assembledfrom a minimum number of sturdy yet inexpensive operating elements,which are adapted to operate smoothly and without substantial variationin speed due to friction or other cause. The control valve assembly isreadily accessible for inspection or repairs, and may easily be adjustedto insure its operation at the desired instant in the cycle of operationof the circuit breaker mechanism.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a fluid pressure operated circuit breaker having relativelymovable contact means, a cylinder, piston means operative upon anincrease in fluid pressure in said cylinder for moving said contactmeans to a circuit closed position, and means for moving said contactmeans to an open circuit position, the combination of supply valve meansoperative to supply fluid under pressure through a communication to saidcylinder, throttle valve means interposed in said communicaticn andhaving an element movable between a position for restricting i'iowtherethrough and an open position for permitting maximum flow, means forbiasing said movable throttle valve element toward own position, apositive latch pivotally mounted on said movable throttle valve elementand engageable with a fixed part for releasably holding said throttlevalve element in the restricting position, a member movable by saidpiston means for moving said throttle valve element against its bias,and said member angaging and releasing said latch during movement ofsaid piston means prior to movement or said throttle valve element.

2. In a fluid pressure operated circuit breaker having relativelymovable contact means, a cylinder. and movable abutment means operativeupon an increase in fluid pressure in said cylinder for moving saidcontact means, the combination of supply valve means operative to supplyfluid under pressure through a communication to said cylinder, throttlevalve means interposed in said communication having a position iorrestricting flow therethrough and an open position for permittingmaximum flow, means for biasing said throttle valve means toward oneposition, a positive latch ior holding said throttle valve means in theother position, a pin and slot lost motion connection between saidmovable abutment means and said-throttle valve means for moving saidthrottle valve means against said biasing means to locked position whenthe pin engages one end oi the slot, and said pin engaging said latchbefore reaching the other end of the slot for releasing said latch priorto any movement of the throttle valve means toward said one position.

3. In a fluid pressure operated circuit breaker having relativelymovable contact means, operating mechanism including a cylinder, apiston operative upon an increase in fluid pressure in said cylinder formoving said contact means to a circuit closed position, and means formoving said contact means to an open circuit position, the combinationof supply valve means operative to supply fluid under pressure through acommunication to said cylinder, throttle valve means interposed in saidcommunication having a position for restricting flow therethrough and anopen position for permitting maximum flow, means for biasing saidthrottle valve means toward open position, a latch element movable withsaid throttle valve means and also movable relative thereto, astationary element engageable by said latch element for releasablyholding said throttle valve means in the restricting position, and alink. member connected to actuate said throttle valve means and havinglost motion cooperation with a movable part of the operating mechanism,and said movable part of the operating mechanism engaging and movingsaid latch to unlatched position upon predetermined movement of saidcontact means toward the closed circuit position.

4. A fluid pressure operated circuit breaker having contact meansmovable to open circuit position and to closed circuit position, anoperating cylinder, a piston operative upon supply 01' fluid underpressure to said cylinder for moving said contact means, fluid pressurecontrol means including a passage for supplying fluid under pressure tosaid cylinder, valve means biased toward one position and movable toanother position to control the rate of flow of fluid under pressurethrough said passage, a latch pivotally connected to said valve meansfor at times locking same in said other position against the biasthereon, a link pivotally connected to said valve means at the pivot ofsaid latch and being movable in response to movement of said contact offluid under pressure to said cylinder for moving said contact means,fluid pressure control means including a passage for supplying fluidunder pressure to said cylinder, valve means biased toward an openposition and movable to a throttling position to control the flow offluid under pressure through said passage, a latch operative to holdsaid valve means in throttling position and having a cam surfacethereon, a link having a lost motion connection with said piston forshifting said valve means .to throttling position so as initially toreduce the rate of supply of fluid under pressure to said cylinderduring subsequent movement of said contact means from the open circuitposition, and an element movable with said piston along said link toengage the cam surface and release said latch after said piston has beenmoved through a predetermined portion of a circuit closing stroke.

6. A fluid pressure operated circuit breaker having contact meansmovable to open circuit position and to closed circuit position, anoperating cylinder, a piston operative upon supply of fluid underpressure to said cylinder for moving said contact means to closedcircuit position, a member operative with said piston, spring meansoperative to move said contact means to open circuit position, fluidpressure control means including a passage for supplying fluid underpressure to said cylinder, a valve biased toward an open position andmovable to a throttling position to control the flow of fluid underpressure through said passage, an elementmounted on said cylinder, 9.positive latch releasable by said member and cooperative with saidelement for at times holding said valve in throttling position.

10 and connected to said valve tor shifting it to the throttlingposition to reduce the rate of flow of fluid under pressure to saidcylinder during initial movement of said contact means from the closedcircuit position, said link means having a slot receiving said memberand constituting a lost-motion connection between said member and saidvalve, and said member in the slot engaging said latch near one end ofthe slot so that said piston must almost complete a contact closingstroke prior to effecting operation of said latch to released position.

7. In a fluid pressure operative circuit breaker of the type includingmovable contact means, means for moving said contact means to an opencircuit position, a movable abutment operative upon an increase in thepressure 01' fluid in a chamber for moving siad contact means to aclosed circuit position, and supply valve means operative to supplyfluid under pressure to said chamber, the combination therewith oithrottle valve means interposed between said supply valve means and saidchamber, said throttle valvemeans including a spring and a movable valveelement biased by said spring toward an open position for permittingsupply of fluid to said chamber at a maximum rate, a latch pivotallyconnected to said movable valve element, stationary means engageablewith said latch for releasably holding said throttle valve means in athrottling position to reduce the rate at which fluid under pressure canbe supplied to said chamber, link means having a lost-motion operativerelation to said movable abutment for efiecting movement of said valveelement to the throttling position only when said abutment is shifted toa position corresponding to the open circuit position of the contactmeans, and means operative with said movable abutment to engage andrelease said latch upon a predetermined movement of said abutment forclosing said contact means.

GERHARD LENTJES.

REFERENCES CITED The following references are .of record in the flle ofthis patent: c

UNITED STATES PATENTS Name Number Date and link means cooperative withsaid member 0 3,3 1 Cumming at a], Sept, 13, 1945

